Document baQ8yXxvvYqvMLZBXdz6jKnn1

UNION CARBIDE PLASTICS COMPANY DIVISION OF UNION CARBIDE CORPORATION 270 PARK AVENUE, NEW YORK 17, N.Y. STANDARD TESTING METHOD DETERMINATION OF FINENESS OF GRIND OF VINYL DISPERSION RESIN WITH THE HEGMAN GAGE METHOD NUMBER WC-J01-G PURPOSE AND This method describes a procedure PAGE LIMITATIONS for determination of the coarse and hard particles in a vinyl DATfe dispersion resin by means of a Hegman Fineness November 16, 1965 of Grind Gage, This method indicates the approx imate size and number of unground particles but not the aver age size of resin particles in the dispersion from the deep md- (0.004 inch) of the tapered channel to the shallow end. Obs r- vations are made of the particles which cause imperfections in- th smooth film surface and of scratches which appear through the dispersion film. Care should be taken to avoid interfer nee from dust or lint on the surface of the sample or on the surfac o the gage and from small air bubbles in the dispersion. The hard particles reading is reported in terms of "Nbrth Standards (NS)", which corresponds to zero at a channel depth of 0.004 inch and to 8 at zero inch. The coarse particle reading is r ported in terms of the number of particles dilch occur within a designated area of the gage. When both the scratch and count readings are to be obtained, the scratch reading should be obtained first and then the count reed ing. A delay in reading the scratch reading can permit th dis persion to flow together and obliterate the scratch. The count reading of a plastisol is not significantly affected by tin . If a dispersion containing volatiles is tested, unusual delay in read ing should be avoided. 2 EQUIPMENT (a) Fineness of Grind Gage (Hegman, two parallel paths 5 1/4 inch long by 1/2 inches wide with channel depth from 0.000 inch s to 0.004 Inches) with scraper, available from the Pr cislon Gage and Tool Company, 320 East Third Street, Dayton, Ohio. (b) Desk lamp w/magnifying lens (Dazor Mfg. Corp., St. Louis, Mo.; Model M-270). (c) Vacuum pump capable of pulling approximately 10 mm of mercury. 3 PROCEDURE (a) Prepare a dispersion of the sample according to Plasti s Standard Testing Method VC-320-D or follow specified instruction for preparing organosols. (b) Deaerate the plastisol under vacuus for approximately 15 mlnut s. BA-441.205 ucc 044645 * WC-101-G Issu No. 4 P 2 of 3 VINYL RESINS HANDBOOK (c) Pour approximately 1/4 gm of the deaerated sample dispersion into the deep end of each clean gage channel of the Tinea sa of Grind Gage. (d) Holding the clean scraper blade perpendicular to the surface and long axis of the gage channel, draw the blade"tawm th length of the gage channel with sufficiently firm pressur to clean the surface of the gage block. The drawdown sp ed should require about 3 seconds for the 3-inch channel 1 ngth. (e) Scratch Reading - Immediately view the gage. Mbt the NS gage reading to the nearest 0.1 unit at the point where th fourth scratch, regardless of length, appears along the channel. (f) Count Reading - The gage is viewed at a right angle to tho axis of the channel and at such an angle from the plane f the gage as to allow the particles on the film surface to be distinguishable when viewed through the magnifying lens of the desk lamp. The reading is obtained by counting the number of particles in a designated North Standard (NS) range on th gage. Care is taken to count all particles visible with no effort taken to distinguish between particles which ext nd above the film surface sufficient to cast a shadow and thos which do not. All particles or imperfections in the fils surface not obviously air bubbles or airborne dirt particl s are counted. The count reading is reported as the number of particl s in a designated area using the NS scale. From 0 to 50 th actual count is reported. Any count over 50 is report d as greater than 50 O SO), (g) Hake four drawdowns, average the resulte, and report th scratch rating to the nearest 0.5 unit and count rating t the nearest unit. Four drawdowns are required to achiev satisfactory ratings. (h) Whenever possible, the use of a single operator to obtain Hegman Count data is recommended. 4 REPORT (a) Complete sample identification (b) Analyst and date (c) HPport the scratch reading to the nearest 0.5 NS rating, using the average of four readings. (d) Report the count reading as number of particles in a specified NS range as directed in Section 3f, using the average of four readings. ucc 044646 Microns Mils Hegaan (NS) Relationship of Ml Reading to Microns and lfils 103 8S 76 63 51 36 33 13 0 4 3310 f f ? i4 f t Scratch reading 5.0 Count reading " 9 TIGURM 1 (? RRA01N0 THR HSGMAM GRIND GAGS ucc- 044647